Wireless communication technology has evolved greatly over the recent years. Recent studies have shown that the wireless spectrum in the U.S. is under-utilized, although most of the spectrum has been assigned to licensees, or primary users. Therefore, spectrum sharing has been proposed to alleviate the spectrum scarcity that prevents new wireless services being deployed. Spectrum sensing is a key enabling technology for secondary access in licensed bands. Spectrum sensing technologies utilize radios that monitor the radio spectrum to detect the presence or absence of primary users. Spectrum sensing complements the geo-location database approach (when a geo-location database is available) by sensing for licensed systems that are not in the database and driving channel selection and coexistence with other secondary systems. Spectrum sensing is vital for bands and incumbent signals where a geo-location database is not available.
With conventional spectrum sensing systems a problem arises when one or more sensing radios that can only minimally contribute, if at all, are included in the group detection process. For example, to achieve a target group probability of false alarm the radios that are capable of detecting the primary signal reduce their detection and false alarm probabilities to accommodate the non-contributing radios. These radios are relying on the performance of the other radios to make up for the reduced detection and false alarm probabilities. Since these radios only contribute marginally, including them is detrimental to group detection performance and wastes valuable resources and bandwidth.